For instance, Patent Document 1 discloses a known technology with respect to an electrical rotary machine. The electrical rotary machine disclosed in the related art comprises; a stator formed with a plurality of cores, each of which is wound with a coil, are held in an inner circumferential surface of a circular cylindrical portion of a holding ring in the form of an annular shape; and a rotor formed in a manner radially facing the stator. Such electrical rotary machine is mainly for use as a motor that drives wheels of hybrid vehicles. The plurality of cores are fixed to the inner circumferential surface of the circular cylindrical portion of the holding ring while keeping the cores arranged in an annular juxtaposition, and then the holding ring is attached to an inside of a motor housing.